Antiphospholipid syndrome (anticardiolipin syndrome, antiphospholipid antibody syndrome, Hughes’ syndrome) is an autoimmune disease and, like most such diseases, it affects more women than men. It’s associated with thrombosis (both arterial and venous), as well as pregnancy-related complications including miscarriage, stillbirth, preterm delivery and severe eclampsia. The condition is characterized by the presence of persistent phospholipid antibodies (aPL) in serum, but this alone is insufficient for diagnosis unless the patient exhibits one or more of the symptoms mentioned above.

APS is due to an autoimmune production of antibodies against certain phospholipids. There are several laboratory tests for detecting these aPL, such as anticardiolipin antibody (aCL), which tests for antibodies against cardiolipin (a phospholipid extracted from beef heart), lupus anticoagulant (LA) which detects antibodies against anionic phospholipids, anti-β2 glycoprotein I (anti-β2 GPI) and anti-prothrombin assay (anti-PT).

APS is called primary APS when it’s not associated with other autoimmune disorders — about half of all cases. When APS is associated with systemic lupus erythematosus, other immunological disorders or malignancy, it’s called secondary APS.

The diagnosis of APS requires:

a) The presence of vascular thrombosis or pregnancy complications (more than 2 unexplained miscarriages before 10th week of gestation, or one or more after 10th week of gestation, or one or more premature birth before 34th week of gestation due to eclampsia).

b) Two positive tests of aPL at least 6 weeks apart (lupus anticoagulant test, moderate-to-high titre aCL, or moderate-to-high titre anti-β2 GPI, etc.). Transient positive aPL may follow some infections or vascular events — the delayed second best serves to exclude these cases.

Worst case scenario

In “catastrophic antiphospholipid syndrome (CAPS)” there’s generalized thrombosis leading to rapid organ failure and high mortality.

Criteria for diagnosis of catastrophic APS includes:

a) Vascular thrombosis in three or more organs or tissues developed simultaneously or within a week, and

b) Evidence of small vessel thrombosis in at least one organ, and

c) Laboratory confirmation of the presence of aPL

Treating APS and CAPS

In patients with arterial thrombosis, aspirin is used to prevent further clotting. For patients with venous thrombosis, long-term oral anticoagulant is used. Women with APS who have suffered pregnancy loss without thrombosis are given heparin (generally low molecular weight heparin) and low dose aspirin during pregnancy, as warfarin is teratogenic.

CAPS is also treated using anticoagulants, often with the addition of corticosteroids, IV immunoglobulin and plasma exchange. But even with all this, mortality from CAPS is still high — about 50%.